I have a 36 gallon aquarium and put a Marineland Visi-Therm 200 Watt Heater in on Thursday night 7pm. Keep in mind this is a new tank for me, never have done this before and have spent and entire week going back and forth getting all the right stuff for the tank. Including a return on an aquian heater because it would never go on. So I researched and All the reviews on this heater, Visi-Therm are excellent but I was under the impression it would heat pretty fast since I have a 200 Watt in a 36 gallon tank. The water temp was at 45' degrees on Thursday night and it is only up to 52' degrees. It has not been 48 hrs yet. Is this going to take a week to get to 77-78' degrees. I have the heater submerged straight up and down, all the way in the water in the back corner since it cannot touch any decorations in my tank. The filter is an aqua clear power filter which hangs outside the tank taking water from the tank and putting it back in from above. I thought maybe this could be cooling down the water and keeping the heating process to a minimum. I have minimum space opened at the top of the tank. There is absolutely no information on the internet as to how long it takes to heat an aquarium. So if this is a stupid question, I give up. I want to start cycling but can't get any fish until I get the heat stabilized in my tank.....